My buddy is having the same issues with his '98 s10 pickup. I noticed he is also missing the spring that sits near the bottom of pin... Not sure if they are related.

 

The spring provides tension for the hinge detent. It helps prevent the door from simply flying wide open when you open it.

 

I'm doing mine soon, I cant remember who wrote it, but they were able to find some greasable door pins. and I remember another one saying he used washers and that prolonged the life a little. I have not tried either one of these methods, but I myself changing my door pins for the fourth time in 2 years. so ill be doing one of the two options.

 

I`ve read people using grade 8 bolts

 

I had the pins replaced 3 years ago when I fixed my drivers side door.
Bronze bushings and pins, properly set and added a reasonable amount of grease.
No problems since.

 

I used the Dorman pin kit on my bottom pin on the drivers door, been there for a couple months and it's still fine. Are you guys sure nothing is bent in your hinge assemblies?